JPS6115850A - Production of ethylene glycol - Google Patents

Abstract

PURPOSE:To produce the titled compound having a wide application field, in improved yield, by the catalytic reaction of carbon monoxide with hydrogen in the presence of a specific trialkylphosphine and an aliphatic carboxylic acid at a specific ratio to the catalyst. CONSTITUTION:The objective compound can be produced by the catalytic reaction of carbon monoxide with hydrogen under high temperature and pressure, preferably at 100-300 deg.C and 50-600kg/cm<2>G, in the presence of (A) a rhodium- containing compound catalyst, (B) a trialkylphosphine having tertiary or quaternary carbon atom at the alpha-position of the alkyl group, and (C) 0.1-200mol, based on 1g-atom of rhodium, of an aliphatic carboxylic acid used as a reaction accelerator. The amount of the component A is preferably 1X10<-5>-10g-atom per 1l of the reaction solution, and the ratio of the P atom in the component B to the Rh atom is preferably selected within the range of 0.5-200.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing ethylene glycol from synthesis gas, a mixed gas of carbon monoxide and hydrogen.

According to the method of the present invention, oxygen-containing compounds can be efficiently produced under relatively mild conditions.

Ethylene glycol is an important basic chemical with a wide range of applications, and there is always hope for an inexpensive industrial production method.

Conventionally, many methods have been proposed for producing ethylene glycol by reacting carbon oxide and hydrogen, using rhodium or ruthenium as a catalyst. Ruthenium catalysts have higher ethylene glycol content than rhodium catalysts by adding an appropriate amount of a selected reaction accelerator, so unless such by-products can be suppressed, ruthenium catalysts cannot be put to practical use. It cannot be said that the value is great.

1.

On the other hand, with rhodium catalysts, the yield of by-products is relatively small compared to the yield of ethylene glycol, which is an important issue for the practical application of this process.

In order to improve these drawbacks of rhodium catalysts, for example, JP-A-48-68509 proposes a method using a Lewis base as a reaction promoter, and JP-A-51-36403 also proposes a method in which a Lewis base is used as a reaction promoter. The alkali metal compound is
JP-A-51-32506 proposes a method using quaternary ammonium salts.

However, in any of these methods, the rate of ethylene glycol production per unit rhodium atom is still low.

The present inventors discovered that when a rhodium catalyst is used in an appropriate amount to coexist with rhodium atoms in ethylene, the present invention can be applied to a method for producing ethylene glycol by catalytically reacting carbon monoxide and hydrogen. , the reaction is carried out using (a) a rhodium-containing compound catalyst, Φ) a trialkylphosphine having a tertiary or quaternary carbon in the alpha position of the alkyl group, and (e) per gram atom of rhodium used. The present invention provides a method for producing ethylene glycol, which is carried out in the presence of 0.1 to 200 moles of aliphatic carboxylic acids.

The rhodium compound used in the method of the present invention is not particularly limited, but examples include metal rhodium, oxides, hydroxides, inorganic acid salts, organic acid salts, and complex compounds. .

More specifically, dirhodium trioxide, rhodium dioxide,
Rhodium hydroxide, rhodium oxalate, rhodium nitrate, rhodium sulfate, rhodium trisacetylacetonate, rhodium acetate, rhodium propionate, rhodium benzoate, rhodium octoate, rhodium dicarbonylacetylacetonate, tetrarhodium dodecacarbonyl, hexarhodium xadecacarbonyl, bis(tetrabutylammonium) dodecalodium tridecacarbonyl, bis(tetraethylammonium) hexalodium pentadecacarbonyl, bis() IJ phenylphosphine)
iminium rhodium tetracarbonyl, acetoxycarbonylbis() IJ cyclohexylphosphine) rhodium, benzoxybis(triisopropylphosphine)
Rhodium, dicarbonyl (η-cyclopentagenyl)
Examples include rhodium, (η-cyclopentadienyl) (η-cyclooctadiene) rhodium, and rhodocene. The amount of rhodium compound used is IX per liter of reaction solution as the concentration of rhodium atoms in the reaction solution.
10=~100 gram atoms, preferably 1 x 10-'~
10 grams atom.

The trialkylphosphine used in the present invention is P
It is represented by the structural formula H1, and R is a C3-2° alkyl group in which the carbon bonded to the phosphorus atom is tertiary or quaternary. Examples of this alkyl group include a 2-propyl group, a 2-butyl group, a tert-butyl group, a 2-pentyl group, a 3-pentyl group, a 2-hexyl group, a 3-hexyl group, and a cyclohexyl group.

These trialkylphosphines can be used alone or in combination of two or more. In either case, the ratio of the phosphorus atom of the trialkylphosphine to the rhodium atom used is greater than 0.2 and less than 500, preferably 0.5, although it varies depending on the type of trialkylphosphine used.
It is necessary to make it exist in the range of ~200.

Aliphatic monocarboxylic acids used as reaction accelerators usually have one carboxyl group for straight chain, branched chain, and alicyclic hydrocarbons having 30 or less carbon atoms. It may have an unsaturated double bond therein. Furthermore, hydrocarbon chains having various substituents such as hydroxy groups, alkoxy groups, aldehyde groups, halogeno groups, nidro groups, aryl groups, N,N-dialkyl groups, and acyl groups may also be used. can.

Specific examples of such compounds include formic acid, acetic acid, propionic acid, butyric acid, acetic anhydride, propionic anhydride, chloroacetic acid, trifluoroacetic acid, maleic acid, succinic acid, citric acid, tartaric acid, lactic acid, acrylic acid, methacrylic acid. , cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, phenylacetic acid, methoxyacetic acid, monomethyl succinate, monoethyl maleate, and the like.

Alternatively, a polymer containing an aliphatic carboxylic acid group in its side chain, such as a copolymer of methacrylic acid or acrylic acid and divinylbenzene, may be used.

The amount of these aliphatic carboxylic acids to be used is in the range of o.i to 200 moles per gram atom of rhodium. If the amount of aliphatic carboxylic acid used is too small, its effect as a promoter is often small1. In the method of the present invention, it is preferable to use a reaction solvent in which ethylene glycol, which is a compound, and the added carboxylic acid form an ester. If you like, you can use stones like those listed below. For example, ethers such as diethyl ether, tetrahydrofuran, dioxane, diethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether, ketones such as acetone, diethyl ketone, and acetophenone, alcohols such as methanol, ethanol, n-butanol, and ethylene glycol, and phenol. , phenols such as methoxyphenol, acetic acid-
Esters such as methyl, ethyl acetate, ethylene glycol diacetate and r-butyrolactone, sulfones such as sulfolane and dimethyl sulfone, sulfoxides such as dimethyl sulfoxide and diethyl sulfoxide, N, N-
Amides such as dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidinone, N-isopropylpyrrolidino/, N-methyl-2-pyridone, N,N
, N,N-tetramethylurine L Substituted ureas such as N,N-dimethylimidazolidinone, phosphoric acid triamides such as hexamethylphosphoric acid triamide and tripiperidinophosphine oxide, benzene, toluene, xylene, tetralin, etc. aromatic hydrocarbons, aliphatic or alicyclic hydrocarbons such as n-hexane, n-octane, cyclohexane, and decalin, nitro compounds such as nitromethane and nitrobenzene, nitriles such as acetonitrile and benzonitrile, dimethyl carbonate, and ethylene carbonate. carbonate esters such as

In the method of the present invention, the reaction is carried out under heated and pressurized conditions. The reaction pressure is usually 1 to 2,000 chest/-G,
Preferably 30-i, o o o Kg/cdG.

More preferably, it is in the range of 50 to aooK9/mG.

At this time, the ratio of carbon monoxide and hydrogen supplied to the reaction system as raw material gas for ethylene glycol production is usually 0.05 to 2 as a molar ratio of carbon monoxide to hydrogen gas.
0, preferably in the range of 0.1 to 10. The reaction temperature is usually 50 to 350°C, preferably 100 to 350°C.
It is in the range of 00°C. Furthermore, the reaction time is usually 0.1
A range of ~20 hours, preferably 0.3 to 10 hours, is used.

Dropping can be carried out batchwise, semi-continuously or continuously.

Example 1 As a reactor, a Hastelloy C autoclave with an internal capacity of 40 animals and capable of withstanding up to eooK9/cnG was used.

The reaction solution was stirred by rotating a Teflon-coated magnetic rotor from outside the reactor by magnetic induction.

18.7 milligrams (0.1 milligram atom) of tetrarhodium dodecacarbonyl, 56. Add θ milligrams (0.2 mmol), 300 milligrams (5 mmol) of acetic acid and 7.5 ynl of dimethylimidazolidinone,
After sealing the reactor, the system was purged several times with an equimolar mixed gas of -carbon oxide and hydrogen, and then 370Kg/1rlG was generated at room temperature.
Pressurely inject the mixed gas until . This reaction solution was heated using an electric furnace until it reached 220° C. while being stirred by external magnetic induction rotation.

The reaction was maintained at this temperature for 2 hours, during which time the gauge pressure decreased from 5 soKy/m to 490Kg/d.

After the reaction was completed, the reactor was rapidly cooled to room temperature, and unreacted gas was purged to obtain a homogeneous reaction solution.

Quantitative analysis of this by gas chromatography revealed that 3.283 mmol of methanol and 2.743 mmol of ethylene glycol were produced as the main products.

Comparative Example 1 In Example 1, the same reaction as in Example 1 was carried out except that acetic acid was not used, and the main products were 1.018 mmol of methanol and 1.92 mmol of ethylene glycol.
Only 3 mmol was produced.

Examples 2 to 5 After purging the inside of a shaking type Hastelloy C autoclave with an internal volume of 3011j with nitrogen, 56° of tetrarhodium dodecacarbonyl (0.3 mg of rhodium atoms) and 48 mg of triisopropylphosphine ( 0.3 mmol), various carboxylic acids shown in Table 1, and N-methylpyrrolidinone 7.5+n
After adding / to each and sealing the reactor, an equimolar mixed gas of -carbon oxide and hydrogen was injected to a predetermined pressure, the reactor was heated in an electric furnace while shaking, and the reaction was carried out at 240°C for 2 hours. I did it. During this time, the reaction pressure decreased within the range shown in Table 1. After the reaction is completed, the reactor is rapidly cooled to room temperature, and then
Unreacted gas was purged to obtain a homogeneous reaction solution.

Quantitative analysis of this by gas chromatography revealed that methanol and ethylene glycol shown in Table 1 were produced as main products.

Comparative Example 2 Same as Example 2 except that no carboxylic acid was added.
The reaction was carried out under the same conditions. The main products are methane, 5.85 mmol of ethylene glycol and 4.5 mmol of ethylene glycol.
2 mmol was produced.

Claims (1)

[Claims] (1) In a method for producing ethylene glycol by catalytically reacting carbon monoxide and hydrogen, the reaction is carried out using (a) a rhodium-containing compound catalyst, (b) a tertiary or quaternary compound at the α-position of the alkyl group. a carbon-containing trialkylphosphine, and (c) 0.1 to 1 gram atom of rhodium used;
A method for producing ethylene glycol, which is carried out in the presence of 200 moles of aliphatic carboxylic acids.